The present disclosure relates to a parallel communication device, and more particularly, to a parallel communication device applied to a solar inverter and a communication method thereof.
A solar power generation system includes a solar module and a solar inverter. Additionally, in the case of a large-scaled solar power generation system, a plurality of solar modules and a plurality of solar inverters are connected to generate power.
At this point, the solar inverter is a power generating device that delivers power to a commercial system by using DC energy generated from a solar module.
However, the capacity of a solar inverter is limited, and accordingly, in order to establish a large capacity of a power generation facility, a system is required, in which a plurality of solar inverters are connected in parallel to provide large output.
When a solar power generating system is configured with such a plurality of solar inverters connected in parallel, the solar inverters need to communicate with each other. A communication method thereof becomes a very important factor in the system configuration.
FIG. 1 is a view illustrating a configuration of a related art solar inverter communication device.
Referring to FIG. 1, the solar inverter communication device includes a master device 10, and at least one slave device 20 connected to the master device 10 through a communication transmission line. FIG. 1 illustrates an example of a parallel communication device in which one master device 10 is connected to three slave devices 20.
In the above parallel communication configuration, a prefix number needs to be assigned to each slave device 20 in order for the master device 10 to communicate with each slave device separately. The prefix number is an identification number to distinguish each slave device 10.
In relation to an operation of the solar inverter communication device, when the master device 10 transmits communication data, all the salve devices 20 connected to a communication network receives the transmitted communication data.
At this point, the transmitted communication data needs to be applied to only a specific slave device that the master device 10 specifies.
Accordingly, the master device 10 inserts prefix information corresponding to a final destination (i.e., a slave device to which the communication data are to be applied) of the communication data into the communication data.
Therefore, each slave device 20 responds to a communication with the master device 10 only when the prefix information in the received communication data corresponds to its own prefix information.
That is, the communication data transmitted through the master device 10 are received by all the salve devices 20, but only the salve device 20 corresponding to the prefix information in the communication data responds to the transmitted communication data. Therefore, parallel communication is possible.
As mentioned above, when communication is performed with a plurality of slave devices 20 connected in parallel, a prefix number is assigned to each solar inverter for mutual distinction, so that data conflicts or communication errors between slave devices, which occur during communication, may be prevented.
However, in order to use a parallel communication through a related art communication method, since a prefix number is assigned to each slave device 20, it needs to be reflected in a communication protocol. Moreover, if there is no function to assign a prefix number to each slave device 20, it is impossible to configure the above parallel communication system.
Furthermore, when a manufacturer attempts to connect different salve devices in parallel but each salve device has different communication protocols, it is impossible to configure a parallel communication. Therefore, when the parallel communication is configured, only slave devices having the same communication protocol need to be selected.